The field of this invention is that of dental devices, and in particular, to an improvement in the construction of a shielded dental contact marker that will mark exclusively surfaces that come into direct forceful contact, and leave unmarked areas of casual or close contact.
In order for teeth to function as an integral part of a masticatory apparatus, they must reduce food introduced into the mouth to small enough size to be mixed with saliva, comfortably swallowed, and efficiently acted on by digestive enzymes. The jaw muscles bring the movable lower jaw against the fixed upper jaw. The lower jaw, approximately L-shaped, has a ball and socket type of joint at the upper extremity of the "L", similar to the knee joint. The lower jaw describes a short arc in its movement about the fulcrum of this joint. The grinding surfaces of all teeth in each arch that work against teeth in the opposite arch must mesh together, or occlude. This brings together the maximum contacting surface of the teeth involved, and the posterior teeth are so shaped into peaks and valley, slopes and ridges, as to enhance the grinding and crushing action of these teeth on foods placed between them.
These raised areas on the teeth are subject to wear, from the abrasive action of some foods, acids, and from grinding against each other. The wear is irregular, and in response to this and other physiological activities, the teeth will frequently shift. These slight alterations in the surface anatomy of the teeth, and in their shifting, as well as irregularities in the growth formation, cause variations in the manner in which the teeth strike against each other and in the way they slide against each other. These variations of contact cause greater force to be exerted on some teeth and on different places on the peaks. Consequently, as the jaws bring these altered teeth into contact, the irregularities and changes of position cause individual teeth, or a few teeth, to come into premature contact, harder contact, interfere with sliding action, and prevent other teeth from coming into appropriate contact. Such interference to normal occlusion are generally called "prematurities," or "high spots."
Prematurities are areas of premature contact where a tooth or a few teeth make initial impact prior to the widely distributed contacts of normal occlusion, or where one or a few teeth bear the brunt of major pressures during tooth sliding movements.
Prematurities may also be man-made, and appear in all artificial teeth and fillings, whether they are "false teeth," silver or plastic fillings, gold inlays, procelain or gold crowns, or multiple crowns called "bridges." For whatever reasons they appear, prematurities are noxious to the healthful function of the teeth, jaws, muscles and joints. They must be reduced or removed by the dentist to bring about the normal relationship and funtion of the teeth and jaws. This is done by grinding, either on the natural teeth or artificial ones, whichever bear the offending places.
These prematurities and high spots are so small as to be unrecognizable by either patient or dentist. The dentist, therefore, must have some way to identify the offending surfaces, which are visually insignificantly tiny portions of the grinding surface of a tooth. The pain and discomfort they cause, however, are out of all proportion to their size. For the identification of the prematurities, or "high spots, " the dentist uses articulating paper. The conventional form of articulating paper has a paper or polymer supporting layer upon which a marking layer of carbon or the like is attached. This is placed between the teeth, and the patient bites down against it and moves the teeth in biting and chewing motions. The material is trapped between the hard, raised tooth surfaces on opposite sides of it. As it is crushed between these raised surfaces, rubbed against, and struck, the pigment of the articulating material stains surfaces it contacts.
Unfortunately, the easily-transferred pigment also stains tooth surfaces that merely rub against it, as the carrier material may be suspended partly in a valley between two or more peaks, or cusps, or has been "dragged" over an upstanding peak, and not from actual firm contact between tooth surfaces. All marks that are not caused by the marking layer being forcibly crushed between opposing hard surfaces in forceful contact are called "false marks." Every articulating material in current and past use has the same major failing: all leave false marks, indistinguishable from true high spot marks. The dentist must grind them all in the attempt to remove the offending areas. Because of this, the process of removing prematurities is very wasteful of sound tooth structure, and also of both the dentists' and the patients' valuable time, not to mention the unnecessary discomfort caused to the patient by the unnecessary grinding of these "false marks."